Hallaxa indecora (Bergh, 1905)
- Location
- Horse Shoes, Okinawa Island (Onna and Yomitan area), Okinawa, Japan
- Date
- 2014/04/24
- Length
- 5mm
- Depth
- 5.0m
- Water temperature
- 22.0℃
Description
A small Dorididae 15 mm long, 13 mm wide and 7 mm high. The body is oval; the completely smooth back is slightly arched; the mantle margin is broad and at times wavy, projecting all around beyond the foot. The rhinophores are small; the gill is composed of 10 simple, rather small leaves. Oral tentacles are absent. The foot is rather narrow with a narrow margin; the not-very-short tail tapers to a point. Neither the rhinophore lamellae nor the tough skin contain hardened cells or spicules. The colour is entirely white, including the small rhinophores and the small gill.Distribution
Type locality: anchorage off Pulu Jedan, east coast of the Aru Islands, Indonesia (Siboga Expedition station 273). The species ranges across the tropical Indo-West Pacific.Etymology
The specific epithet indecora is the feminine form of the Latin adjective compounded from the negative in- and decorus ("graceful, ornate"), meaning "unadorned, plain". The choice of "indecora" evidently sets up an opposition with the previously known H. decorata ("the adorned one").Remarks
Originally described as Halla indecora. The genus name Halla was preoccupied in another animal group (Annelida); the replacement name Hallaxa was accordingly proposed, yielding the current combination Hallaxa indecora.References
- ハラックサウミウシ（新稱）, Baba K. (1949). Opisthobranchia of Sagami Bay collected by His Majesty the Emperor of Japan (相模湾産後鰓類図譜). Iwanami Shoten, Tokyo. 4+2+194+7 pp., pls. 1-50.
- Hallaxa indecora (genus context), Miller M.C. (1987). Hallaxa gilva, a new dorid nudibranch (Gastropoda: Opisthobranchia) from New Zealand. New Zealand Journal of Zoology. 14(1): 123-129.
- 高岡生物研究会. (2002). 日本海のウミウシ. 第2版.
A Kindle field guide by the site author
Kimoto N. (2026). Sea Slugs of Japan & the Indo-Pacific, 2nd Edition.
Kindle Edition
View on Amazon PR (Amazon Associates)Seasonality
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Photos of Hallaxa indecora
Tag:
Same Genus Nudibranchs
Similar Colors Nudibranchs
Academic Database
Sea slug observation data is available in international marine biodiversity databases.